Pfizer begins human trials of possible coronavirus vaccine

Knvul Sheikh, The New York Times

Posted at May 05 2020 11:04 PM

Pfizer and the German pharmaceutical company BioNTech announced that their potential coronavirus vaccine began human trials in the United States on Monday. If the tests are successful, the vaccine could be ready for emergency use here as early as September.

The two firms are jointly developing a vaccine candidate based on genetic material known as messenger RNA, which carries the instructions for cells to make proteins. By injecting a specially designed messenger RNA into the body, the vaccine could potentially tell cells how to make the spike protein of the coronavirus without actually making a person sick.

Because the virus typically uses this protein as a key to unlock and take over lung cells, the vaccine could train a healthy immune system to produce antibodies to fight off an infection. The technology also has the advantage of being faster to produce, and tends to be more stable than traditional vaccines, which use weakened virus strains.

Moderna, Inovio, CanSino and several other pharmaceutical companies are trying similar approaches, some of which began the first phase of tests in humans a few weeks ago. But no vaccine made with this technology for other viruses has ever reached the global market.

Pfizer, which is based in New York, and BioNTech injected the first human volunteers with their vaccine candidate, called BNT162, in Germany last month. The experimental shot was given to just 12 healthy adults, although the trial will eventually expand to 200 participants.

In the United States, the drug companies plan to test the vaccine on 360 healthy volunteers for the first stage of the study, adding up to 8,000 volunteers by the end of the second stage. The study will be conducted at New York University’s Grossman School of Medicine, the University of Maryland School of Medicine, the University of Rochester Medical Center and the Cincinnati Children’s Hospital Medical Center.

Participants will be divided into groups to compare four variations of the vaccine, each representing a format of messenger RNA with instructions to make a distinct piece of the spike protein machinery. Doctors will closely monitor the participants’ antibody levels, liver enzymes and other indicators of possible side effects.

“Vaccines are given to healthy people to keep them healthy, so they have to be very, very safe,” said Dr. Mark Mulligan, an infectious disease specialist at NYU.

Testing multiple candidates in parallel is one way the companies hope to compress the amount of time it takes to gather enough proof to apply for emergency-use approval by the Food and Drug Administration. Once that approval is received, Pfizer and BioNTech could distribute the first few million doses here.

As soon as pharmaceutical companies can show evidence that a vaccine is effective and has produced no serious harms, they can apply for this kind of approval, which allows doctors to administer the vaccine to those most in need. But more detailed study results may still be needed to persuade federal regulators to approve a candidate for the broader public.

Given the need to quash the coronavirus, vaccine-makers around the world are racing to speed up their timelines for development, a process that typically takes years. But companies are making extraordinary efforts to stagger trials and, in some cases, skip essential steps, such as animal testing.

Some experts have warned that expecting an approved vaccine within 18 months — as Dr. Anthony Fauci, the nation’s leading expert on infectious diseases, has suggested — is overly optimistic.

A group of scientists developing a vaccine at Oxford University in England say that even 18 months is too long to wait for a vaccine. With emergency approval, they say they are aiming to have the first few million doses of their vaccine available in September.

Pfizer and BioNTech say they hope to have several million doses by then, too, if everything goes well with these human trials.

“We need to think differently, we need to think faster,” said Dr. Mikael Dolsten, Pfizer’s chief scientific officer. “If we get hit with a second wave of coronavirus infections in October at the same time as the flu, things will be much worse than what we’ve already experienced.”